If an artist like Beck says that Spotify isn't paying him enough, you have to ask two things. One, is Beck expecting to get paid like he was getting paid back in the '90s and two, is Beck paying his sidemen a little too much?
It is never going to be enough. Services like Spotify are there to enrich themselves. They're there to maximize their profits and reap the rewards. If you consider them a modern record company, then all you can conclude is that the economics of artistic exploitation have continued into the modern era. The people making the devices and providing the Internet service to people love things like Spotify--it allows them to sell things to people for a good profit. People forget that the iPod was never given away free nor was the Internet connection.